How to make the factory radio recognize there is an AUX input connected?
 

I bought a Pie X3 AUX interface that provides 3 Aux inputs when plugged to the 14pins cd plug (CD changer connection) of the factory radio. The problem I have is that the CD/AUX button on the factory radio that is supposed to enable switching to a CD changer does not do anything. Pressing this button has no effect at all. Is there something that needs to be customized on the factory radio to make it recognize that there is an AUX connected?
Thanks